Align tabs from right to left using ttk.Notebook widget

In Oblivion's line:

s.configure('TNotebook', tabposition='ne')

the 'ne' bit can be:

nw => above (north) and to the left (west)
ne => above and to the right (east)
en => to the right (east), at the top
es => to the right (east), at the bottom
se => below (south) and to the right (east)
sw => below (south) and to the left (west)
ws => to the left (west) and to the bottom (south)
wn => to the left (west) and at top

'nw' is, I guess, the more common one, but an application may require it otherwise.

There is actually a style option for this - tabposition.

import tkinter as tk
from tkinter import ttk

root = tk.Tk()
root.minsize(300, 300)
root.geometry("1000x700")

s = ttk.Style()
s.configure('TNotebook', tabposition='ne') #'ne' as in compass direction

box = ttk.Notebook(root, width=1000, height=650)

tab1 = tk.Frame(root)
tab2 = tk.Frame(root)
tab3 = tk.Frame(root)

box.add(tab1, text="tab1")
box.add(tab2, text="tab2")
box.add(tab3, text="tab3")

box.pack(side=tk.TOP)

root.mainloop()